/Engine/Source/Runtime/Engine/Classes/GameFramework/GameModeBase.h
Used to notify the game type that it is ok to update a player's gameplay specific muting information now. The playercontroller needs to notify the server when it is possible to do so or the unique net id will be incorrect and the muting not work.
virtual void UpdateGameplayMuteList ( [APlayerController](API\Runtime\Engine\GameFramework\APlayerController) * aPlayer )